Field of the Invention
Embodiments of the invention relate to a touch screen panel, and more particularly, to a metal mesh type touch screen panel capable of solving a limitation of the size of the touch screen panel resulting from resistance capacitance (RC) delay.
Discussion of the Related Art
In recent years, display devices, such as a liquid crystal display, an electroluminescent display, and a plasma display panel, having a fast response time, low power consumption, and an excellent color reproduction rate, have been in the spotlight. These display devices have been used for various electronic products such as a television, a monitor for a computer, a laptop computer, a mobile phone, a display unit of a refrigerator, a personal digital assistant, and an automated teller machine. In general, these display devices interface with various input devices such as a keyboard, a mouse, and a digitizer. However, in order to use a separate input device such as the keyboard and the mouse, a user has to deal with the inconveniences of learning how to use it and taking up space, thus making it difficult to improve the degree of completion of the product. Therefore, the demand for input devices that are convenient and easy to use and reduce an erroneous operation is gserialing more and more. In response to this demand, a touch screen panel for enabling a user to input information by directly touching the screen with his or her hand or a pen was suggested.
Because the touch screen panel has a simple configuration, causes few erroneous operations, can perform an input operation without a separate input device, and offers the convenience of allowing the user to quickly and easily manipulate content displayed on the screen, the touch screen panel is applied to various display devices.
Touch screen panels are classified into a resistive type, a capacitive type, an electromagnetic type, etc. based on a method for sensing a touched portion. The resistive touch screen panel determines a touched position by a voltage gradient based on changes of resistance in a state where a DC voltage is applied to metal electrodes formed on an upper plate or a lower plate. The capacitive touch screen panel senses a touched position based on changes in capacitance generated in an upper plate or a lower plate when the user touches an equipotential conductive film formed on the upper or lower plate. The electromagnetic touch screen panel senses a touched portion by reading an LC value induced when an electronic pen touches a conductive film.
Hereinafter, a related art capacitive touch screen panel is described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of a related art capacitive touch screen panel. FIG. 2 is a cross-sectional view taken along lines I-I′, II-II′, and III-III′ of FIG. 1.
As shown in FIGS. 1 and 2, the related art capacitive touch screen panel includes an electrode forming part A, a routing wiring part B, and a pad part C.
The electrode forming part A includes a plurality of first touch electrode serials TS arranged in parallel in a first direction (for example, x-axis direction), a plurality of second touch electrode serials RS arranged in parallel in a second direction (for example, y-axis direction) crossing the first direction, and an insulating layer INS for electrically insulating the first touch electrode serials TS and the second touch electrode serials RS.
Each of the first touch electrode serials TS includes a plurality of first electrode patterns 31 and a plurality of first connection patterns 21 for connecting the adjacent first electrode patterns 31. The adjacent first electrode patterns 31 are connected to the first connection patterns 21 exposed through contact holes CH formed in the insulating layer INS. Each of the second touch electrode serials RS includes a plurality of second electrode patterns 33 and a plurality of second connection patterns 34 for connecting the adjacent second electrode patterns 33. The second electrode patterns 33 and the second connection patterns 34 are integrated to form an integral body.
The routing wiring part B is formed outside the electrode forming part A. The routing wiring part B includes a plurality of first routing wires TW respectively connected to the plurality of first touch electrode serials TS and a plurality of second routing wires RW respectively connected to the plurality of second touch electrode serials RS.
The pad part C includes a plurality of first pads TP respectively connected to the plurality of first touch electrode serials TS through the plurality of first routing wires TW and a plurality of second pads RP respectively connected to the plurality of second touch electrode serials RS through the plurality of second routing wires RW.
In the above-described related art capacitive touch screen panel, the first touch electrode serials TS and the second touch electrode serials RS are formed of a transparent electrode material such as indium tin oxide (ITO). However, ITO used in the first and second touch electrode serials has an electric resistance much greater than a general metal material, and the first and second touch electrode serials are formed in a surface electrode form. Therefore, as the size of the touch screen panel increases, the RC delay, which is a factor reducing the touch accuracy of the touch screen panel, increases. Accordingly, a way capable of reducing the RC delay of the touch screen panel has been demanded so as to solve the problem.